You can now create 3D models by waving your smartphone around an object

Apr. 2, 2015 | By Alec

Even if you rarely check out a technology blog, it cannot have escaped your attention that even regular smartphones are increasingly being used as mediums or tools for the latest technological innovations. Just look at those budget virtual reality goggles that rely on app-based software or those basic 3D modeling apps. Really the big option that still hasn’t been converted into app shape is 3D scanning – but not for long. Researchers from the Pennsylvania-based Carnegie Mellon University have developed a method for doing exactly that.

Now as you might have realized, 3D scanners can potentially be hugely beneficial for 3D printing purposes. After all, it could save us from a lot of modeling hours when we need to replicate an original piece. However, there is a lot more to 3D scanning than simply taking a three dimensional photo – a scanner needs to make accurate measurements of just about every part of the object in question, which makes laser technology a perfect (though woefully expensive) option.

Until now, our smartphones have not yet been capable of measuring distances between points (and thus making 3D printable files), but CMU researchers have developed a very clever way of solving that problem. Quite literally, it only requires the wave of a hand. As associate professor of Robotics Simon Lucey reveals, they rely on the inertial measurement units (or IMUs) that are embedded in every phone these accelerometers are used to automatically switch a smartphone screen orientation based on the user’s positioning, from landscape to portrait or the other way around.

While ‘noisy’, Lucey argues that these relatively inaccurate sensors are powerful enough to be used to calibrate 3D models when waving the phone around an object. ‘We’ve been able to get accuracies with cheap sensors that we hadn’t imagined,” Lucey says on the CMU website. ‘With a face tracker program, we are able to measure the distance between a person’s pupils within half a millimeter.’ Distances that, obviously, mean that this technology can be used to make 3D printable digital models.

Lucey was previously part of a startup concept called Smart Fit, that created 3D models of peoples’ faces to digitally fit glasses to them. During that process, his team also ran into scanning difficulties. ‘We figured there had to be a better way to do this,’ Lucey said. He and his team already reported their tests with IMUs at the European Conference on Computer Vision. ‘The trajectory we create with these cheap IMUs will ‘drift’ over time, but the vision element we create is very accurate. So we can use the 3-D model to correct for the errors caused by the IMU, even as we use the IMU to estimate the dimensions of the model.’

While no practical app-based use has yet been developed for this amazing low-budget scanning technique, the potential is evident. ‘The amazing thing is that we can turn any smartphone into a ruler — no special hardware, no depth sensors, just your regular smart device,’ Lucey says, further adding that high frame-rate video cameras will result in even better scanning results. With a high frame-rate camera’s we can excite the IMU by moving the phone faster, without corrupting the images.’

While a large number of interesting low-cost applications can be developed for this technology, we are obviously most interested in potential for hobbyist 3D printing. Could this mean we are already carrying a 3D scanner around in our pocket? It looks like creating 3D printable designs is about to become easier than ever before.